Blogs Car Info Our Show Deals Mechanics Files Vehicle Donation

'05 Outback XT fuel system rust

115,000 miles, adult driven. Hard cranking, took into dealer. Replaced 4 injectors - cylinder 2 misfiring. Showed me return gas line clogged with brownish material. Dealer stymied.

Now, Subaru headquarters diagnoses replacing all steel fuel lines, fuel rails, fuel pump…full of rust from inside. Tank looks Ok, as does filler neck. Asking $2300 on top of $800 for injectors. Premium gas used always, added Drygas seasonally as needed.

Question: where the heck would rust come from? What can I do to prevent this problem again? Love the car…would like to get 200,000 from it. HELP!

I recommend against replacing the entire fuel system at this point. Ask them to connect fuel cleaner to the fuel rail and run the engine on the fuel cleaner. Also ask them to add fuel cleaner to the gas tank.
IMO the dealer is stumped and wants to replace everything. In their view, if everything is replaced, the problem will be solved.
I once resurrected a car that had sat for five years. I drained and cleaned the tank, replaced the fuel pump and the fuel filter. It ran great on fresh gasoline. I didn’t need to replace all of the lines and the injectors. The only reason the pump had to be replaced was that the fuel had degraded over time and clogged up the pump.

db4690 has the right idea I think. This is an usual symptom if the car has been regularly driven and not sitting parked for weeks or months. Has it ever sat parked and unused for a month or more? Just driving the car keeps the fuel lines flushed, with the fuel filter doing its job and all. It’s possible you got a really bad tank of gasoline one time though,which could clog both the fuel pump and the fuel filter. One option would be to replace the fuel filter and possibly drain and clean the fuel tank and pump screens I guess. See if that fixes the problem.

On the other hand, it may be that Subaru techs have seen this problem occuring in many vehicles of this model and year and has found from experience the best solution is to do exactly what they recommend. Maybe ask an inde who specializes in Subarus for a second opinion.

Am I missing something here? The dealer changed 4 pricy fuel injectors leaving you with a No. 2 cylinder misfire, and NOW they want to change everything but the kitchen sink after the fact?

If rust is that bad then I rhetorically ask why someone did not notice this during an injector swap and with the fuel rail off.

If there really is a lot of rust in the system then the new injectors are now contaminated. Rust can clog up screens in the fuel injectors and no amount or type of cleaner will clean it out.

The rust could have come from an underground gasoline storage tank but the bigger issue to me would be how someone could remove fuel rails, change injectors, and be oblivious to any fuel contamination problem.

I wonder how you’d get rust in a FI system of a relatively newer car. Has it been sitting for a long time in a driveway with gas in the tank or something? If there’s no rust in the tank, where can it possibly be coming from? Are they sure that brownish stuff was indeed rust?

No, the car is used almost every day. The longest it ever sat was a couple of one-week vacations, and the last was months ago. They showed me the return fuel line…clogged like a bad artery with brownish “mud”. My problem is that I need the car…I can’t keep running back to the dealer every few days for a “band-aid” fix.

It was running fine when I took it in. I had to turn the key two or three times intermittently to get the engine to catch…that was my original complaint. I buy gas at the same couple of stations…never a problem with my wife’s Legacy. I’m stumped.

As noted in the posts above, you are reporting quite unusual symptoms and a equally unusual diagnosis. No one here can say “yeah” or “neah” from an internet description, but it might be a good idea – you may end up money ahead – to take this car to an independent mechanic who specializes in Subarus for their opinion. Ask other Subaru owners you know for a local mechanic recommendation. Best of luck.

It could still be due to contamination in the underground tanks and it could just be luck of the draw that you (and maybe a few others) picked it up. There’s always the possibility of contamination from the gasoline delivery truck, etc.

The hard starting per the way you described it almost sounds like a loss or residual fuel pressure when the car is not being used. A certain amount of pressure should remain in the lines at all times so the engine will start instantly. This is not a rare problem with any make of car and is usually due to a faulty fuel pump check valve or fuel pressure sensor; all depending on make.

What I still have an issue with here is why the dealer would change out 4 expensive fuel injectors which require removal of the fuel rails. Any problem with rust or gunk should have been easily noticeable at that time.
This would be akin to having an engine with filthy motor oil and changing the filter only while leaving the dirty oil in there.

You should get another opinion on this because if the system is as rusty or mudded up as claimed there should have been some symptoms other than an iffy startup.
Just call me dubious…

Ok. Here’s where we stand after several discussions with the mechanic and service writer…

When the hard starting was investigated, rust was found in the bowl of a fuel injector and dropping pressure was evidenced. Leaky FI because of partial clog was diagnosed. All 4 injectors were replaced…“If one is bad, the others will go soon and we’ll have to open up the engine again then.”

200 miles later, cylinder 2 was mis-firing. Again, rust is found. Upon further examination, return fuel line and fuel rails found partially clogged. After calls to Subie headquarters, the following was recommended: replace entire system.

So…modified plan

Tank inspected. Minor amount of gunk…flushed.
Filler neck inspected…OK.
Replace all steel fuel lines. Can’t be flushed.
Flush rubber fuel lines.
Replace fuel rail.
Replace fuel filter.
Replace fuel regulator.

They don’t know where rust/gunk/sludge came from. My cars are filled at the same 2 - 3 gas stations…no trouble with wife’s car. Never sat idle for long periods of time. Drygas occasionally in winter.

There are no local independent garages for second opinion that know Subies. Car is immobile, so a big dealer out of area is inaccessible. I don’t have much technical engine knowledge, so…

$3100 (- 10 to 15% discount agreed on) poorer. 12 month - 12,000 mile warranty. 2013 loaner awd vehicle as long as my car is in garage. I guess that’s the best I can do. They sound as straightforward as I guess I can expect…seem to answer my questions as best they.

So…thank you for the time and information you offered. I truly appreciate it.

Good on them for offering-up a loaner, and good on you for getting the car back on the road. Check the owner’s manual for recommended intervals for fuel filter replacement going forward I guess is about all you can do. Best of luck.

I wish you the best and you might keep us informed of what happens with your car. My cynicism about the process remains though. :slight_smile:

Why they would need to call Subaru over an alleged rust issue is beyond me.

I was on the phone to my adult son, who wondered if ethanol (typically 10% here) could be clogging up the engine of the 2005 car. He went to school in Indiana and knew corn farmers who discussed the pitfalls of ethanol for owners of older cars. He’s now in Florida, where boat owners deal with ethanol degradation. Could this be a contributing factor in my 2005 Subie?

Would it benefit me to try to find a local gas station that doesn’t use ethanol in their 93 octane gas?

Ethanol can certainly be a problem on some cars. What have you been running in it; E15, E85, etc?

For what it’s worth, I live in farm country with a number of farmers around here who grow the corn but will not use the fuel where it ends up.
Most gas stations around here will not carry Ethanol and advertise the fact.

Boat engines and small engines used in mowers, chainsaws, and so on are even more prevalent to suffering problems due to sitting idle because Ethanol gasoline can degrade quickly and turn into what is essentially mush.

The only thing I can say is: Use the fuel that contains the least ethanol possible. Fuel systems designed for E85 have been extensively modified because ethanol is extremely aggressive. This has been brought up countless times in numerous magazines, trade papers, etc.

So if you’ve been using E85, now is the time to stop. Hopefully you haven’t. I wouldn’t even use E85 in a vehicle designed to use it.

I think they initially did you a disservice by replacing the injectors and sending you on your way. Enough junk gets to an injector and they think it won’t happen again on the new ones? Should have looked further.

Second strike, your list does not have replace all injectors again. Bet one or more are gunked up again.

Car is immobile, so a big dealer out of area is inaccessible


Good luck. I sincerely hope they get it right this time for your sake.

OK…update time. The fuel lines were not in stock anywhere in the US, so had to be ordered from Japan. Later, found puffer valves in fuel rail had some sediment, so these had to be ordered from Japan. Car in dealer’s garage for 6 weeks now. In the meantime, I’m driving a new awe Rogue loaner car for free. At least, this keeps my Subie out the salt for one winter.

I’ve asked dealer to save all replaced parts for me…not that I can tell anything from them, but at least I’ll know they were replaced.

Will post again when the car is on the road. The dealer guarantees 100% and will warranty it for 12 months/12,000 miles.

Big question in my head…if the filler neck is OK< and the tank had very little sediment that they could flush out so as not to replace the tank, where did the rust/sludge come from??

Every gas station in the state is mandated to use 10% ethanol in automotive gas. The only “pure” gas is marine fuel, but driving out to the end of the dock risks a bigger problem. :slight_smile: Since the dealer (and Subie headquarters) hasn’t seen this particular problem, I guess the ethanol is probably not the cause.